# SQL手册

## 元数据操作

### 1、数据库管理

#### 创建数据库

```sql
CREATE DATABASE root.ln
```

#### 查看数据库

```sql
show databases
show databases root.*
show databases root.**
```

#### 删除数据库

```sql
DELETE DATABASE root.ln
DELETE DATABASE root.sgcc
DELETE DATABASE root.**
```

#### 统计数据库数量

```sql
count databases
count databases root.*
count databases root.sgcc.*
count databases root.sgcc
```

### 2、时间序列管理

#### 创建时间序列

```sql
create timeseries root.ln.wf01.wt01.status with datatype=BOOLEAN,encoding=PLAIN
create timeseries root.ln.wf01.wt01.temperature with datatype=FLOAT,encoding=RLE
create timeseries root.ln.wf02.wt02.hardware with datatype=TEXT,encoding=PLAIN
create timeseries root.ln.wf02.wt02.status with datatype=BOOLEAN,encoding=PLAIN
create timeseries root.sgcc.wf03.wt01.status with datatype=BOOLEAN,encoding=PLAIN
create timeseries root.sgcc.wf03.wt01.temperature with datatype=FLOAT,encoding=RLE
```

- 简化版

```sql
create timeseries root.ln.wf01.wt01.status BOOLEAN encoding=PLAIN
create timeseries root.ln.wf01.wt01.temperature FLOAT encoding=RLE
create timeseries root.ln.wf02.wt02.hardware TEXT encoding=PLAIN
create timeseries root.ln.wf02.wt02.status BOOLEAN encoding=PLAIN
create timeseries root.sgcc.wf03.wt01.status BOOLEAN encoding=PLAIN
create timeseries root.sgcc.wf03.wt01.temperature FLOAT encoding=RLE
```

- 错误提示

```sql
create timeseries root.ln.wf02.wt02.status WITH DATATYPE=BOOLEAN, ENCODING=TS_2DIFF
> error: encoding TS_2DIFF does not support BOOLEAN
```

#### 创建对齐时间序列

```sql
CREATE ALIGNED TIMESERIES root.ln.wf01.GPS(latitude FLOAT encoding=PLAIN compressor=SNAPPY, longitude FLOAT encoding=PLAIN compressor=SNAPPY) 
```

#### 删除时间序列

```sql
delete timeseries root.ln.wf01.wt01.status
delete timeseries root.ln.wf01.wt01.temperature, root.ln.wf02.wt02.hardware
delete timeseries root.ln.wf02.*
drop timeseries root.ln.wf02.*
```

#### 查看时间序列

```sql
SHOW TIMESERIES
SHOW TIMESERIES <Path>
show timeseries root.**
show timeseries root.ln.**
show timeseries root.ln.** limit 10 offset 10
show timeseries root.ln.** where timeseries contains 'wf01.wt'
show timeseries root.ln.** where dataType=FLOAT
SHOW LATEST TIMESERIES
```

#### 统计时间序列数量

```sql
COUNT TIMESERIES root.**
COUNT TIMESERIES root.ln.**
COUNT TIMESERIES root.ln.*.*.status
COUNT TIMESERIES root.ln.wf01.wt01.status
COUNT TIMESERIES root.** WHERE TIMESERIES contains 'sgcc' 
COUNT TIMESERIES root.** WHERE DATATYPE = INT64
COUNT TIMESERIES root.** WHERE TAGS(unit) contains 'c' 
COUNT TIMESERIES root.** WHERE TAGS(unit) = 'c' 
COUNT TIMESERIES root.** WHERE TIMESERIES contains 'sgcc' group by level = 1
COUNT TIMESERIES root.** GROUP BY LEVEL=1
COUNT TIMESERIES root.ln.** GROUP BY LEVEL=2
COUNT TIMESERIES root.ln.wf01.* GROUP BY LEVEL=2
```

#### 标签点管理

```sql
create timeseries root.turbine.d1.s1(temprature) with datatype=FLOAT, encoding=RLE, compression=SNAPPY tags(tag1=v1, tag2=v2) attributes(attr1=v1, attr2=v2)
```

- 重命名标签或属性

```sql
ALTER timeseries root.turbine.d1.s1 RENAME tag1 TO newTag1
```

- 重新设置标签或属性的值

```sql
ALTER timeseries root.turbine.d1.s1 SET newTag1=newV1, attr1=newV1
```

- 删除已经存在的标签或属性

```sql
ALTER timeseries root.turbine.d1.s1 DROP tag1, tag2
```

- 添加新的标签

```sql
ALTER timeseries root.turbine.d1.s1 ADD TAGS tag3=v3, tag4=v4
```

- 添加新的属性

```sql
ALTER timeseries root.turbine.d1.s1 ADD ATTRIBUTES attr3=v3, attr4=v4
```

- 更新插入别名，标签和属性

```sql
ALTER timeseries root.turbine.d1.s1 UPSERT ALIAS=newAlias TAGS(tag2=newV2, tag3=v3) ATTRIBUTES(attr3=v3, attr4=v4)
```

- 使用标签作为过滤条件查询时间序列

```sql
SHOW TIMESERIES (<`PathPattern`>)? timeseriesWhereClause
```

返回给定路径的下的所有满足条件的时间序列信息：

```sql
ALTER timeseries root.ln.wf02.wt02.hardware ADD TAGS unit=c
ALTER timeseries root.ln.wf02.wt02.status ADD TAGS description=test1
show timeseries root.ln.** where TAGS(unit)='c'
show timeseries root.ln.** where TAGS(description) contains 'test1'
```

- 使用标签作为过滤条件统计时间序列数量

```sql
COUNT TIMESERIES (<`PathPattern`>)? timeseriesWhereClause
COUNT TIMESERIES (<`PathPattern`>)? timeseriesWhereClause GROUP BY LEVEL=<INTEGER>
```

返回给定路径的下的所有满足条件的时间序列的数量：

```sql
count timeseries
count timeseries root.** where TAGS(unit)='c'
count timeseries root.** where TAGS(unit)='c' group by level = 2
```

创建对齐时间序列：

```sql
create aligned timeseries root.sg1.d1(s1 INT32 tags(tag1=v1, tag2=v2) attributes(attr1=v1, attr2=v2), s2 DOUBLE tags(tag3=v3, tag4=v4) attributes(attr3=v3, attr4=v4))
```

支持查询：

```sql
show timeseries where TAGS(tag1)='v1'
```

### 3、时间序列路径管理

#### 查看路径的所有子路径

```sql
SHOW CHILD PATHS pathPattern
- 查询 root.ln 的下一层：show child paths root.ln
- 查询形如 root.xx.xx.xx 的路径：show child paths root.*.*
```
#### 查看路径的所有子节点

```sql
SHOW CHILD NODES pathPattern

- 查询 root 的下一层：show child nodes root
- 查询 root.ln 的下一层 ：show child nodes root.ln
```
#### 查看设备

```sql
IoTDB> show devices

IoTDB> show devices root.ln.**
```
##### 查看设备及其 database 信息

```sql
IoTDB> show devices with database

IoTDB> show devices root.ln.** with database
```
#### 统计节点数

```sql
IoTDB > COUNT NODES root.** LEVEL=2

IoTDB > COUNT NODES root.ln.** LEVEL=2

IoTDB > COUNT NODES root.ln.wf01.* LEVEL=3

IoTDB > COUNT NODES root.**.temperature LEVEL=3
```
#### 统计设备数量

```sql
IoTDB> show devices

IoTDB> count devices

IoTDB> count devices root.ln.**
```
### 4、设备模板管理


![img](https://alioss.timecho.com/docs/img/%E6%A8%A1%E6%9D%BF.png)
![img](https://alioss.timecho.com/docs/img/template.jpg)


#### 创建设备模板

```Go
CREATE DEVICE TEMPLATE <templateName> ALIGNED? '(' <measurementId> <attributeClauses> [',' <measurementId> <attributeClauses>]+ ')'
```

创建包含两个非对齐序列的设备模板
```sql
IoTDB> create device template t1 (temperature FLOAT encoding=RLE, status BOOLEAN encoding=PLAIN compression=SNAPPY)
```
创建包含一组对齐序列的设备模板
```sql
IoTDB> create device template t2 aligned (lat FLOAT encoding=Gorilla, lon FLOAT encoding=Gorilla)
```
#### 挂载设备模板
```sql
IoTDB> set DEVICE TEMPLATE t1 to root.sg1
```
#### 激活设备模板
```sql
IoTDB> create timeseries using DEVICE TEMPLATE on root.sg1.d1

IoTDB> set DEVICE TEMPLATE t1 to root.sg1.d1

IoTDB> set DEVICE TEMPLATE t2 to root.sg1.d2

IoTDB> create timeseries using device template on root.sg1.d1

IoTDB> create timeseries using device template on root.sg1.d2
```
#### 查看设备模板
```sql
IoTDB> show device templates
```
- 查看某个设备模板下的物理量
```sql
IoTDB> show nodes in device template t1
```
- 查看挂载了某个设备模板的路径
```sql
IoTDB> show paths set device template t1
```
- 查看使用了某个设备模板的路径（即模板在该路径上已激活，序列已创建）
```sql
IoTDB> show paths using device template t1
```
#### 解除设备模板
```sql
IoTDB> delete timeseries of device template t1 from root.sg1.d1
```
```sql
IoTDB> deactivate device template t1 from root.sg1.d1
```
批量处理
```sql
IoTDB> delete timeseries of device template t1 from root.sg1.*, root.sg2.*
```
```sql
IoTDB> deactivate device template t1 from root.sg1.*, root.sg2.*
```
#### 卸载设备模板
```sql
IoTDB> unset device template t1 from root.sg1.d1
```
#### 删除设备模板
```sql
IoTDB> drop device template t1
```
### 5、数据存活时间管理

#### 设置 TTL
```sql
IoTDB> set ttl to root.ln 3600000
```
```sql
IoTDB> set ttl to root.sgcc.** 3600000
```
```sql
IoTDB> set ttl to root.** 3600000
```
#### 取消 TTL
```sql
IoTDB> unset ttl to root.ln
```
```sql
IoTDB> unset ttl to root.sgcc.**
```
```sql
IoTDB> unset ttl to root.**
```

#### 显示 TTL
```sql
IoTDB> SHOW ALL TTL
```
```sql
IoTDB> SHOW TTL ON StorageGroupNames
```
## 写入数据

### 1、写入单列数据
```sql
IoTDB > insert into root.ln.wf02.wt02(timestamp,status) values(1,true)
```
```sql
IoTDB > insert into root.ln.wf02.wt02(timestamp,hardware) values(1, 'v1'),(2, 'v1')
```
### 2、写入多列数据
```sql
IoTDB > insert into root.ln.wf02.wt02(timestamp, status, hardware) values (2, false, 'v2')
```
```sql
IoTDB > insert into root.ln.wf02.wt02(timestamp, status, hardware) VALUES (3, false, 'v3'),(4, true, 'v4')
```
### 3、使用服务器时间戳
```sql
IoTDB > insert into root.ln.wf02.wt02(status, hardware) values (false, 'v2')
```
### 4、写入对齐时间序列数据
```sql
IoTDB > create aligned timeseries root.sg1.d1(s1 INT32, s2 DOUBLE)
```
```sql
IoTDB > insert into root.sg1.d1(timestamp, s1, s2) aligned values(1, 1, 1)
```
```sql
IoTDB > insert into root.sg1.d1(timestamp, s1, s2) aligned values(2, 2, 2), (3, 3, 3)
```
```sql
IoTDB > select * from root.sg1.d1
```
### 5、加载 TsFile 文件数据

load '<path/dir>' [sglevel=int][verify=true/false][onSuccess=delete/none]

#### 通过指定文件路径(绝对路径)加载单 tsfile 文件

- `load '/Users/Desktop/data/1575028885956-101-0.tsfile'`
- `load '/Users/Desktop/data/1575028885956-101-0.tsfile' verify=true`
- `load '/Users/Desktop/data/1575028885956-101-0.tsfile' verify=false`
- `load '/Users/Desktop/data/1575028885956-101-0.tsfile' sglevel=1`
- `load '/Users/Desktop/data/1575028885956-101-0.tsfile' onSuccess=delete`
- `load '/Users/Desktop/data/1575028885956-101-0.tsfile' verify=true sglevel=1`
- `load '/Users/Desktop/data/1575028885956-101-0.tsfile' verify=false sglevel=1`
- `load '/Users/Desktop/data/1575028885956-101-0.tsfile' verify=true onSuccess=none`
- `load '/Users/Desktop/data/1575028885956-101-0.tsfile' verify=false sglevel=1 onSuccess=delete`

#### 通过指定文件夹路径(绝对路径)批量加载文件

- `load '/Users/Desktop/data'`
- `load '/Users/Desktop/data' verify=false`
- `load '/Users/Desktop/data' verify=true`
- `load '/Users/Desktop/data' verify=true sglevel=1`
- `load '/Users/Desktop/data' verify=false sglevel=1 onSuccess=delete`

## 删除数据

### 1、删除单列数据
```sql
delete from root.ln.wf02.wt02.status where time<=2017-11-01T16:26:00;
```
```sql
delete from root.ln.wf02.wt02.status where time>=2017-01-01T00:00:00 and time<=2017-11-01T16:26:00;
```
```sql
delete from root.ln.wf02.wt02.status where time < 10
```
```sql
delete from root.ln.wf02.wt02.status where time <= 10
```
```sql
delete from root.ln.wf02.wt02.status where time < 20 and time > 10
```
```sql
delete from root.ln.wf02.wt02.status where time <= 20 and time >= 10
```
```sql
delete from root.ln.wf02.wt02.status where time > 20
```
```sql
delete from root.ln.wf02.wt02.status where time >= 20
```
```sql
delete from root.ln.wf02.wt02.status where time = 20
```
出错：
```sql
delete from root.ln.wf02.wt02.status where time > 4 or time < 0

Msg: 303: Check metadata error: For delete statement, where clause can only contain atomic

expressions like : time > XXX, time <= XXX, or two atomic expressions connected by 'AND'
```

删除时间序列中的所有数据：
```sql
delete from root.ln.wf02.wt02.status
```
### 2、删除多列数据
```sql
delete from root.ln.wf02.wt02.* where time <= 2017-11-01T16:26:00;
```
声明式的编程方式：
```sql
IoTDB> delete from root.ln.wf03.wt02.status where time < now()

Msg: The statement is executed successfully.
```
## 数据查询

### 1、基础查询

#### 时间过滤查询
```sql
select temperature from root.ln.wf01.wt01 where time < 2017-11-01T00:08:00.000
```
#### 根据一个时间区间选择多列数据
```sql
select status, temperature from root.ln.wf01.wt01 where time > 2017-11-01T00:05:00.000 and time < 2017-11-01T00:12:00.000;
```
#### 按照多个时间区间选择同一设备的多列数据
```sql
select status, temperature from root.ln.wf01.wt01 where (time > 2017-11-01T00:05:00.000 and time < 2017-11-01T00:12:00.000) or (time >= 2017-11-01T16:35:00.000 and time <= 2017-11-01T16:37:00.000);
```
#### 按照多个时间区间选择不同设备的多列数据
```sql
select wf01.wt01.status, wf02.wt02.hardware from root.ln where (time > 2017-11-01T00:05:00.000 and time < 2017-11-01T00:12:00.000) or (time >= 2017-11-01T16:35:00.000 and time <= 2017-11-01T16:37:00.000);
```
#### 根据时间降序返回结果集
```sql
select * from root.ln.** where time > 1 order by time desc limit 10;
```
### 2、选择表达式

#### 使用别名
```sql
select s1 as temperature, s2 as speed from root.ln.wf01.wt01;
```
#### 运算符

#### 函数

不支持：
```sql
select s1, count(s1) from root.sg.d1;

select sin(s1), count(s1) from root.sg.d1;

select s1, count(s1) from root.sg.d1 group by ([10,100),10ms);
```
##### 时间序列查询嵌套表达式

示例 1：
```sql
select a,

​       b,

​       ((a + 1) * 2 - 1) % 2 + 1.5,

​       sin(a + sin(a + sin(b))),

​       -(a + b) * (sin(a + b) * sin(a + b) + cos(a + b) * cos(a + b)) + 1

from root.sg1;
```
示例 2：
```sql
select (a + b) * 2 + sin(a) from root.sg

示例 3：

select (a + *) / 2  from root.sg1

示例 4：

select (a + b) * 3 from root.sg, root.ln
```
##### 聚合查询嵌套表达式

示例 1：
```sql
select avg(temperature),

​       sin(avg(temperature)),

​       avg(temperature) + 1,

​       -sum(hardware),

​       avg(temperature) + sum(hardware)

from root.ln.wf01.wt01;
```
示例 2：
```sql
select avg(*), 

​           (avg(*) + 1) * 3 / 2 -1 

from root.sg1
```
示例 3：
```sql
select avg(temperature),

​       sin(avg(temperature)),

​       avg(temperature) + 1,

​       -sum(hardware),

​       avg(temperature) + sum(hardware) as custom_sum

from root.ln.wf01.wt01

GROUP BY([10, 90), 10ms);
```
#### 最新点查询

SQL 语法：

```Go
select last <Path> [COMMA <Path>]* from < PrefixPath > [COMMA < PrefixPath >]* <whereClause> [ORDER BY TIMESERIES (DESC | ASC)?]
```

查询 root.ln.wf01.wt01.status 的最新数据点
```sql
IoTDB> select last status from root.ln.wf01.wt01
```
查询 root.ln.wf01.wt01 下 status，temperature 时间戳大于等于 2017-11-07T23:50:00 的最新数据点
```sql
IoTDB> select last status, temperature from root.ln.wf01.wt01 where time >= 2017-11-07T23:50:00
```
 查询 root.ln.wf01.wt01 下所有序列的最新数据点，并按照序列名降序排列
```sql
IoTDB> select last * from root.ln.wf01.wt01 order by timeseries desc;
```
### 3、查询过滤条件

#### 时间过滤条件

选择时间戳大于 2022-01-01T00:05:00.000 的数据：
```sql
select s1 from root.sg1.d1 where time > 2022-01-01T00:05:00.000;
```
选择时间戳等于 2022-01-01T00:05:00.000 的数据：
```sql
select s1 from root.sg1.d1 where time = 2022-01-01T00:05:00.000;
```
选择时间区间 [2017-11-01T00:05:00.000, 2017-11-01T00:12:00.000) 内的数据：
```sql
select s1 from root.sg1.d1 where time >= 2022-01-01T00:05:00.000 and time < 2017-11-01T00:12:00.000;
```
#### 值过滤条件

选择值大于 36.5 的数据：
```sql
select temperature from root.sg1.d1 where temperature > 36.5;
```
选择值等于 true 的数据：
```sql
select status from root.sg1.d1 where status = true;
```
选择区间 [36.5,40] 内或之外的数据：
```sql
select temperature from root.sg1.d1 where temperature between 36.5 and 40;
```
```sql
select temperature from root.sg1.d1 where temperature not between 36.5 and 40;
```
选择值在特定范围内的数据：
```sql
select code from root.sg1.d1 where code in ('200', '300', '400', '500');
```
选择值在特定范围外的数据：
```sql
select code from root.sg1.d1 where code not in ('200', '300', '400', '500');
```
选择值为空的数据:
```sql
select code from root.sg1.d1 where temperature is null;
```
选择值为非空的数据:
```sql
select code from root.sg1.d1 where temperature is not null;
```
#### 模糊查询

查询 `root.sg.d1` 下 `value` 含有`'cc'`的数据
```sql
IoTDB> select * from root.sg.d1 where value like '%cc%'
```
查询 `root.sg.d1` 下 `value` 中间为 `'b'`、前后为任意单个字符的数据
```sql
IoTDB> select * from root.sg.device where value like '_b_'
```
查询 root.sg.d1 下 value 值为26个英文字符组成的字符串
```sql
IoTDB> select * from root.sg.d1 where value regexp '^[A-Za-z]+$'
```

查询 root.sg.d1 下 value 值为26个小写英文字符组成的字符串且时间大于100的
```sql
IoTDB> select * from root.sg.d1 where value regexp '^[a-z]+$' and time > 100
```

### 4、分段分组聚合

#### 未指定滑动步长的时间区间分组聚合查询
```sql
select count(status), max_value(temperature) from root.ln.wf01.wt01 group by ([2017-11-01T00:00:00, 2017-11-07T23:00:00),1d);
```
#### 指定滑动步长的时间区间分组聚合查询
```sql
select count(status), max_value(temperature) from root.ln.wf01.wt01 group by ([2017-11-01 00:00:00, 2017-11-07 23:00:00), 3h, 1d);
```
滑动步长可以小于聚合窗口
```sql
select count(status), max_value(temperature) from root.ln.wf01.wt01 group by ([2017-11-01 00:00:00, 2017-11-01 10:00:00), 4h, 2h);
```
#### 按照自然月份的时间区间分组聚合查询
```sql
select count(status) from root.ln.wf01.wt01 where time > 2017-11-01T01:00:00 group by([2017-11-01T00:00:00, 2019-11-07T23:00:00), 1mo, 2mo);
```
每个时间间隔窗口内都有数据
```sql
select count(status) from root.ln.wf01.wt01 group by([2017-10-31T00:00:00, 2019-11-07T23:00:00), 1mo, 2mo);
```
#### 左开右闭区间
```sql
select count(status) from root.ln.wf01.wt01 group by ((2017-11-01T00:00:00, 2017-11-07T23:00:00],1d);
```
#### 与分组聚合混合使用

统计降采样后的数据点个数
```sql
select count(status) from root.ln.wf01.wt01 group by ((2017-11-01T00:00:00, 2017-11-07T23:00:00],1d), level=1;
```
加上滑动 Step 的降采样后的结果也可以汇总
```sql
select count(status) from root.ln.wf01.wt01 group by ([2017-11-01 00:00:00, 2017-11-07 23:00:00), 3h, 1d), level=1;
```
#### 路径层级分组聚合

统计不同 database 下 status 序列的数据点个数
```sql
select count(status) from root.** group by level = 1
```
 统计不同设备下 status 序列的数据点个数
```sql
select count(status) from root.** group by level = 3
```
统计不同 database 下的不同设备中 status 序列的数据点个数
```sql
select count(status) from root.** group by level = 1, 3
```
查询所有序列下温度传感器 temperature 的最大值
```sql
select max_value(temperature) from root.** group by level = 0
```
查询某一层级下所有传感器拥有的总数据点数
```sql
select count(*) from root.ln.** group by level = 2
```
#### 标签分组聚合

##### 单标签聚合查询
```sql
SELECT AVG(temperature) FROM root.factory1.** GROUP BY TAGS(city);
```
##### 多标签聚合查询
```sql
SELECT avg(temperature) FROM root.factory1.** GROUP BY TAGS(city, workshop);
```
##### 基于时间区间的标签聚合查询
```sql
SELECT AVG(temperature) FROM root.factory1.** GROUP BY ([1000, 10000), 5s), TAGS(city, workshop);
```
#### 差值分段聚合
```sql
group by variation(controlExpression[,delta][,ignoreNull=true/false])
```
##### delta=0时的等值事件分段
```sql
select __endTime, avg(s1), count(s2), sum(s3) from root.sg.d group by variation(s6)
```
指定ignoreNull为false
```sql
select __endTime, avg(s1), count(s2), sum(s3) from root.sg.d group by variation(s6, ignoreNull=false)
```
##### delta!=0时的差值事件分段
```sql
select __endTime, avg(s1), count(s2), sum(s3) from root.sg.d group by variation(s6, 4)
```
#### 条件分段聚合
```sql
group by condition(predict,[keep>/>=/=/<=/<]threshold,[,ignoreNull=true/false])
```
查询至少连续两行以上的charging_status=1的数据
```sql
select max_time(charging_status),count(vehicle_status),last_value(soc) from root.** group by condition(charging_status=1,KEEP>=2,ignoreNull=true)
```
当设置`ignoreNull`为false时，遇到null值为将其视为一个不满足条件的行，得到结果原先的分组被含null的行拆分
```sql
select max_time(charging_status),count(vehicle_status),last_value(soc) from root.** group by condition(charging_status=1,KEEP>=2,ignoreNull=false)
```
#### 会话分段聚合
```sql
group by session(timeInterval)
```
按照不同的时间单位设定时间间隔
```sql
select __endTime,count(*) from root.** group by session(1d)
```
和`HAVING`、`ALIGN BY DEVICE`共同使用
```sql
select __endTime,sum(hardware) from root.ln.wf02.wt01 group by session(50s) having sum(hardware)>0 align by device
```
#### 点数分段聚合
```sql
group by count(controlExpression, size[,ignoreNull=true/false])
```
select count(charging_stauts), first_value(soc) from root.sg group by count(charging_status,5) 

当使用ignoreNull将null值也考虑进来
```sql
select count(charging_stauts), first_value(soc) from root.sg group by count(charging_status,5,ignoreNull=false) 
```
### 5、聚合结果过滤

不正确的：
```sql
select count(s1) from root.** group by ([1,3),1ms) having sum(s1) > s1

select count(s1) from root.** group by ([1,3),1ms) having s1 > 1

select count(s1) from root.** group by ([1,3),1ms), level=1 having sum(d1.s1) > 1

select count(d1.s1) from root.** group by ([1,3),1ms), level=1 having sum(s1) > 1
```
SQL 示例：
```sql
 select count(s1) from root.** group by ([1,11),2ms), level=1 having count(s2) > 2;

 select count(s1), count(s2) from root.** group by ([1,11),2ms) having count(s2) > 1 align by device;
```
### 6、结果集补空值
```sql
FILL '(' PREVIOUS | LINEAR | constant (, interval=DURATION_LITERAL)? ')'
```
#### `PREVIOUS` 填充
```sql
select temperature, status from root.sgcc.wf03.wt01 where time >= 2017-11-01T16:37:00.000 and time <= 2017-11-01T16:40:00.000 fill(previous);
```
#### `PREVIOUS` 填充并指定填充超时阈值
```sql
select temperature, status from root.sgcc.wf03.wt01 where time >= 2017-11-01T16:37:00.000 and time <= 2017-11-01T16:40:00.000 fill(previous, 2m);
```
#### `LINEAR` 填充
```sql
select temperature, status from root.sgcc.wf03.wt01 where time >= 2017-11-01T16:37:00.000 and time <= 2017-11-01T16:40:00.000 fill(linear);
```
#### 常量填充
```sql
select temperature, status from root.sgcc.wf03.wt01 where time >= 2017-11-01T16:37:00.000 and time <= 2017-11-01T16:40:00.000 fill(2.0);
```
使用 `BOOLEAN` 类型的常量填充
```sql
select temperature, status from root.sgcc.wf03.wt01 where time >= 2017-11-01T16:37:00.000 and time <= 2017-11-01T16:40:00.000 fill(true);
```
### 7、查询结果分页

#### 按行分页

 基本的 `LIMIT` 子句
```sql
select status, temperature from root.ln.wf01.wt01 limit 10
```
带 `OFFSET` 的 `LIMIT` 子句
```sql
select status, temperature from root.ln.wf01.wt01 limit 5 offset 3
```
`LIMIT` 子句与 `WHERE` 子句结合
```sql
select status,temperature from root.ln.wf01.wt01 where time > 2017-11-01T00:05:00.000 and time< 2017-11-01T00:12:00.000 limit 5 offset 3
```
 `LIMIT` 子句与 `GROUP BY` 子句组合
```sql
select count(status), max_value(temperature) from root.ln.wf01.wt01 group by ([2017-11-01T00:00:00, 2017-11-07T23:00:00),1d) limit 4 offset 3
```
#### 按列分页

 基本的 `SLIMIT` 子句
```sql
select * from root.ln.wf01.wt01 where time > 2017-11-01T00:05:00.000 and time < 2017-11-01T00:12:00.000 slimit 1
```
带 `SOFFSET` 的 `SLIMIT` 子句
```sql
select * from root.ln.wf01.wt01 where time > 2017-11-01T00:05:00.000 and time < 2017-11-01T00:12:00.000 slimit 1 soffset 1
```
`SLIMIT` 子句与 `GROUP BY` 子句结合
```sql
select max_value(*) from root.ln.wf01.wt01 group by ([2017-11-01T00:00:00, 2017-11-07T23:00:00),1d) slimit 1 soffset 1
```
`SLIMIT` 子句与 `LIMIT` 子句结合
```sql
select * from root.ln.wf01.wt01 limit 10 offset 100 slimit 2 soffset 0
```
### 8、排序

时间对齐模式下的排序
```sql
select * from root.ln.** where time <= 2017-11-01T00:01:00 order by time desc;
```
设备对齐模式下的排序
```sql
select * from root.ln.** where time <= 2017-11-01T00:01:00 order by device desc,time asc align by device;
```
在时间戳相等时按照设备名排序
```sql
select * from root.ln.** where time <= 2017-11-01T00:01:00 order by time asc,device desc align by device;
```
没有显式指定时
```sql
select * from root.ln.** where time <= 2017-11-01T00:01:00 align by device;
```
对聚合后的结果进行排序
```sql
select count(*) from root.ln.** group by ((2017-11-01T00:00:00.000+08:00,2017-11-01T00:03:00.000+08:00],1m) order by device asc,time asc align by device
```
### 9、查询对齐模式

#### 按设备对齐
```sql
select * from root.ln.** where time <= 2017-11-01T00:01:00 align by device;
```
### 10、查询写回（SELECT INTO）

#### 整体描述
```sql
selectIntoStatement

​    : SELECT

​        resultColumn [, resultColumn] ...

​        INTO intoItem [, intoItem] ...

​        FROM prefixPath [, prefixPath] ...

​        [WHERE whereCondition]

​        [GROUP BY groupByTimeClause, groupByLevelClause]

​        [FILL ({PREVIOUS | LINEAR | constant} (, interval=DURATION_LITERAL)?)]

​        [LIMIT rowLimit OFFSET rowOffset]

​        [ALIGN BY DEVICE]

​    ;


intoItem

​    : [ALIGNED] intoDevicePath '(' intoMeasurementName [',' intoMeasurementName]* ')'

​    ;
```
按时间对齐，将 `root.sg` database 下四条序列的查询结果写入到 `root.sg_copy` database 下指定的四条序列中
```sql
IoTDB> select s1, s2 into root.sg_copy.d1(t1), root.sg_copy.d2(t1, t2), root.sg_copy.d1(t2) from root.sg.d1, root.sg.d2;
```
按时间对齐，将聚合查询的结果存储到指定序列中
```sql
IoTDB> select count(s1 + s2), last_value(s2) into root.agg.count(s1_add_s2), root.agg.last_value(s2) from root.sg.d1 group by ([0, 100), 10ms);
```
按设备对齐
```sql
IoTDB> select s1, s2 into root.sg_copy.d1(t1, t2), root.sg_copy.d2(t1, t2) from root.sg.d1, root.sg.d2 align by device;
```
按设备对齐，将表达式计算的结果存储到指定序列中
```sql
IoTDB> select s1 + s2 into root.expr.add(d1s1_d1s2), root.expr.add(d2s1_d2s2) from root.sg.d1, root.sg.d2 align by device;
```
#### 使用变量占位符

##### 按时间对齐（默认）

###### （1）目标设备不使用变量占位符 & 目标物理量列表使用变量占位符
```

select s1, s2

into root.sg_copy.d1(::), root.sg_copy.d2(s1), root.sg_copy.d1(${3}), root.sg_copy.d2(::)

from root.sg.d1, root.sg.d2;
```

该语句等价于：
```

select s1, s2

into root.sg_copy.d1(s1), root.sg_copy.d2(s1), root.sg_copy.d1(s2), root.sg_copy.d2(s2)

from root.sg.d1, root.sg.d2;
```

###### （2）目标设备使用变量占位符 & 目标物理量列表不使用变量占位符

```
select d1.s1, d1.s2, d2.s3, d3.s4 

into ::(s1_1, s2_2), root.sg.d2_2(s3_3), root.${2}_copy.::(s4)

from root.sg;
```

###### （3）目标设备使用变量占位符 & 目标物理量列表使用变量占位符

```
select * into root.sg_bk.::(::) from root.sg.**;
```

##### 按设备对齐（使用 `ALIGN BY DEVICE`）

###### （1）目标设备不使用变量占位符 & 目标物理量列表使用变量占位符
```

select s1, s2, s3, s4

into root.backup_sg.d1(s1, s2, s3, s4), root.backup_sg.d2(::), root.sg.d3(backup_${4})

from root.sg.d1, root.sg.d2, root.sg.d3

align by device;
```

###### （2）目标设备使用变量占位符 & 目标物理量列表不使用变量占位符
```

select avg(s1), sum(s2) + sum(s3), count(s4)

into root.agg_${2}.::(avg_s1, sum_s2_add_s3, count_s4)

from root.**

align by device;
```

###### （3）目标设备使用变量占位符 & 目标物理量列表使用变量占位符
```

select * into ::(backup_${4}) from root.sg.** align by device;
```

#### 指定目标序列为对齐序列
```

select s1, s2 into root.sg_copy.d1(t1, t2), aligned root.sg_copy.d2(t1, t2) from root.sg.d1, root.sg.d2 align by device;
```
## 运维语句
生成对应的查询计划
```
explain select s1,s2 from root.sg.d1
```
执行对应的查询语句，并获取分析结果
```
explain analyze select s1,s2 from root.sg.d1 order by s1
```
## 运算符

更多见文档[Operator-and-Expression](../Reference/Function-and-Expression.md#算数运算符和函数)

### 算数运算符

更多见文档 [Arithmetic Operators and Functions](../Reference/Function-and-Expression.md#算数运算符和函数)

```sql
select s1, - s1, s2, + s2, s1 + s2, s1 - s2, s1 * s2, s1 / s2, s1 % s2 from root.sg.d1
```

### 比较运算符

更多见文档[Comparison Operators and Functions](../Reference/Function-and-Expression.md#比较运算符和函数)

```sql
# Basic comparison operators
select a, b, a > 10, a <= b, !(a <= b), a > 10 && a > b from root.test;

# `BETWEEN ... AND ...` operator
select temperature from root.sg1.d1 where temperature between 36.5 and 40;
select temperature from root.sg1.d1 where temperature not between 36.5 and 40;

# Fuzzy matching operator: Use `Like` for fuzzy matching
select * from root.sg.d1 where value like '%cc%'
select * from root.sg.device where value like '_b_'

# Fuzzy matching operator: Use `Regexp` for fuzzy matching
select * from root.sg.d1 where value regexp '^[A-Za-z]+$'
select * from root.sg.d1 where value regexp '^[a-z]+$' and time > 100
select b, b like '1%', b regexp '[0-2]' from root.test;

# `IS NULL` operator
select code from root.sg1.d1 where temperature is null;
select code from root.sg1.d1 where temperature is not null;

# `IN` operator
select code from root.sg1.d1 where code in ('200', '300', '400', '500');
select code from root.sg1.d1 where code not in ('200', '300', '400', '500');
select a, a in (1, 2) from root.test;
```

### 逻辑运算符

更多见文档[Logical Operators](../Reference/Function-and-Expression.md#逻辑运算符)

```sql
select a, b, a > 10, a <= b, !(a <= b), a > 10 && a > b from root.test;
```

## 内置函数

更多见文档[Operator-and-Expression](../Reference/Function-and-Expression.md#聚合函数)

### Aggregate Functions

更多见文档[Aggregate Functions](../Reference/Function-and-Expression.md#聚合函数)

```sql
select count(status) from root.ln.wf01.wt01;

select count_if(s1=0 & s2=0, 3), count_if(s1=1 & s2=0, 3) from root.db.d1;
select count_if(s1=0 & s2=0, 3, 'ignoreNull'='false'), count_if(s1=1 & s2=0, 3, 'ignoreNull'='false') from root.db.d1;

select time_duration(s1) from root.db.d1;
```

### 算数函数

更多见文档[Arithmetic Operators and Functions](../Reference/Function-and-Expression.md#数学函数)

```sql
select s1, sin(s1), cos(s1), tan(s1) from root.sg1.d1 limit 5 offset 1000;
select s4,round(s4),round(s4,2),round(s4,-1) from root.sg1.d1;
```

### 比较函数

更多见文档[Comparison Operators and Functions](../Reference/Function-and-Expression.md#比较运算符和函数)

```sql
select ts, on_off(ts, 'threshold'='2') from root.test;
select ts, in_range(ts, 'lower'='2', 'upper'='3.1') from root.test;
```

### 字符串处理函数

更多见文档[String Processing](../Reference/Function-and-Expression.md#字符串处理)

```sql
select s1, string_contains(s1, 's'='warn') from root.sg1.d4;
select s1, string_matches(s1, 'regex'='[^\\s]+37229') from root.sg1.d4;
select s1, length(s1) from root.sg1.d1
select s1, locate(s1, "target"="1") from root.sg1.d1
select s1, locate(s1, "target"="1", "reverse"="true") from root.sg1.d1
select s1, startswith(s1, "target"="1") from root.sg1.d1
select s1, endswith(s1, "target"="1") from root.sg1.d1
select s1, s2, concat(s1, s2, "target1"="IoT", "target2"="DB") from root.sg1.d1
select s1, s2, concat(s1, s2, "target1"="IoT", "target2"="DB", "series_behind"="true") from root.sg1.d1
select s1, substring(s1 from 1 for 2) from root.sg1.d1
select s1, replace(s1, 'es', 'tt') from root.sg1.d1
select s1, upper(s1) from root.sg1.d1
select s1, lower(s1) from root.sg1.d1
select s3, trim(s3) from root.sg1.d1
select s1, s2, strcmp(s1, s2) from root.sg1.d1
select strreplace(s1, "target"=",", "replace"="/", "limit"="2") from root.test.d1
select strreplace(s1, "target"=",", "replace"="/", "limit"="1", "offset"="1", "reverse"="true") from root.test.d1
select regexmatch(s1, "regex"="\d+\.\d+\.\d+\.\d+", "group"="0") from root.test.d1
select regexreplace(s1, "regex"="192\.168\.0\.(\d+)", "replace"="cluster-$1", "limit"="1") from root.test.d1
select regexsplit(s1, "regex"=",", "index"="-1") from root.test.d1
select regexsplit(s1, "regex"=",", "index"="3") from root.test.d1
```

### 数据类型转换函数

更多见文档[Data Type Conversion Function](../Reference/Function-and-Expression.md#数据类型转换)

```sql
SELECT cast(s1 as INT32) from root.sg
```

### 常序列生成函数

更多见文档[Constant Timeseries Generating Functions](../Reference/Function-and-Expression.md#常序列生成函数)

```sql
select s1, s2, const(s1, 'value'='1024', 'type'='INT64'), pi(s2), e(s1, s2) from root.sg1.d1; 
```

### 选择函数

更多见文档[Selector Functions](../Reference/Function-and-Expression.md#选择函数)

```sql
select s1, top_k(s1, 'k'='2'), bottom_k(s1, 'k'='2') from root.sg1.d2 where time > 2020-12-10T20:36:15.530+08:00;
```

### 区间查询函数

更多见文档[Continuous Interval Functions](../Reference/Function-and-Expression.md#区间查询函数)

```sql
select s1, zero_count(s1), non_zero_count(s2), zero_duration(s3), non_zero_duration(s4) from root.sg.d2;
```

### 趋势计算函数

更多见文档[Variation Trend Calculation Functions](../Reference/Function-and-Expression.md#趋势计算函数)

```sql
select s1, time_difference(s1), difference(s1), non_negative_difference(s1), derivative(s1), non_negative_derivative(s1) from root.sg1.d1 limit 5 offset 1000; 

SELECT DIFF(s1), DIFF(s2) from root.test;
SELECT DIFF(s1, 'ignoreNull'='false'), DIFF(s2, 'ignoreNull'='false') from root.test;
```

### 采样函数

更多见文档[Sample Functions](../Reference/Function-and-Expression.md#采样函数)。
### 时间序列处理函数

更多见文档[Sample Functions](../Reference/Function-and-Expression.md#时间序列处理函数)。

```sql
select equal_size_bucket_random_sample(temperature,'proportion'='0.1') as random_sample from root.ln.wf01.wt01;
select equal_size_bucket_agg_sample(temperature, 'type'='avg','proportion'='0.1') as agg_avg, equal_size_bucket_agg_sample(temperature, 'type'='max','proportion'='0.1') as agg_max, equal_size_bucket_agg_sample(temperature,'type'='min','proportion'='0.1') as agg_min, equal_size_bucket_agg_sample(temperature, 'type'='sum','proportion'='0.1') as agg_sum, equal_size_bucket_agg_sample(temperature, 'type'='extreme','proportion'='0.1') as agg_extreme, equal_size_bucket_agg_sample(temperature, 'type'='variance','proportion'='0.1') as agg_variance from root.ln.wf01.wt01;
select equal_size_bucket_m4_sample(temperature, 'proportion'='0.1') as M4_sample from root.ln.wf01.wt01;
select equal_size_bucket_outlier_sample(temperature, 'proportion'='0.1', 'type'='avg', 'number'='2') as outlier_avg_sample, equal_size_bucket_outlier_sample(temperature, 'proportion'='0.1', 'type'='stendis', 'number'='2') as outlier_stendis_sample, equal_size_bucket_outlier_sample(temperature, 'proportion'='0.1', 'type'='cos', 'number'='2') as outlier_cos_sample, equal_size_bucket_outlier_sample(temperature, 'proportion'='0.1', 'type'='prenextdis', 'number'='2') as outlier_prenextdis_sample from root.ln.wf01.wt01;

select M4(s1,'timeInterval'='25','displayWindowBegin'='0','displayWindowEnd'='100') from root.vehicle.d1
select M4(s1,'windowSize'='10') from root.vehicle.d1
```

### 时间序列处理函数

更多见文档[Time-Series](../Reference/Function-and-Expression.md#时间序列处理)

```sql
select change_points(s1), change_points(s2), change_points(s3), change_points(s4), change_points(s5), change_points(s6) from root.testChangePoints.d1
```

## 数据质量函数库

更多见文档[Operator-and-Expression](../Reference/UDF-Libraries.md)

### 数据质量

更多见文档[Data-Quality](../Reference/UDF-Libraries.md#数据质量)

```sql
# Completeness
select completeness(s1) from root.test.d1 where time <= 2020-01-01 00:00:30
select completeness(s1,"window"="15") from root.test.d1 where time <= 2020-01-01 00:01:00

# Consistency
select consistency(s1) from root.test.d1 where time <= 2020-01-01 00:00:30
select consistency(s1,"window"="15") from root.test.d1 where time <= 2020-01-01 00:01:00

# Timeliness
select timeliness(s1) from root.test.d1 where time <= 2020-01-01 00:00:30
select timeliness(s1,"window"="15") from root.test.d1 where time <= 2020-01-01 00:01:00

# Validity
select Validity(s1) from root.test.d1 where time <= 2020-01-01 00:00:30
select Validity(s1,"window"="15") from root.test.d1 where time <= 2020-01-01 00:01:00

# Accuracy
select Accuracy(t1,t2,t3,m1,m2,m3) from root.test
```

### 数据画像

更多见文档[Data-Profiling](../Reference/UDF-Libraries.md#数据画像)

```sql
# ACF
select acf(s1) from root.test.d1 where time <= 2020-01-01 00:00:05

# Distinct
select distinct(s2) from root.test.d2

# Histogram
select histogram(s1,"min"="1","max"="20","count"="10") from root.test.d1

# Integral
select integral(s1) from root.test.d1 where time <= 2020-01-01 00:00:10
select integral(s1, "unit"="1m") from root.test.d1 where time <= 2020-01-01 00:00:10

# IntegralAvg
select integralavg(s1) from root.test.d1 where time <= 2020-01-01 00:00:10

# Mad
select mad(s0) from root.test
select mad(s0, "error"="0.01") from root.test

# Median
select median(s0, "error"="0.01") from root.test

# MinMax
select minmax(s1) from root.test

# Mode
select mode(s2) from root.test.d2

# MvAvg
select mvavg(s1, "window"="3") from root.test

# PACF
select pacf(s1, "lag"="5") from root.test

# Percentile
select percentile(s0, "rank"="0.2", "error"="0.01") from root.test

# Quantile
select quantile(s0, "rank"="0.2", "K"="800") from root.test

# Period
select period(s1) from root.test.d3

# QLB
select QLB(s1) from root.test.d1

# Resample
select resample(s1,'every'='5m','interp'='linear') from root.test.d1
select resample(s1,'every'='30m','aggr'='first') from root.test.d1
select resample(s1,'every'='30m','start'='2021-03-06 15:00:00') from root.test.d1

# Sample
select sample(s1,'method'='reservoir','k'='5') from root.test.d1
select sample(s1,'method'='isometric','k'='5') from root.test.d1

# Segment
select segment(s1, "error"="0.1") from root.test

# Skew
select skew(s1) from root.test.d1

# Spline
select spline(s1, "points"="151") from root.test

# Spread
select spread(s1) from root.test.d1 where time <= 2020-01-01 00:00:30

# Stddev
select stddev(s1) from root.test.d1

# ZScore
select zscore(s1) from root.test
```

### 异常检测

更多见文档[Anomaly-Detection](../Reference/UDF-Libraries.md#异常检测)

```sql
# IQR
select iqr(s1) from root.test

# KSigma
select ksigma(s1,"k"="1.0") from root.test.d1 where time <= 2020-01-01 00:00:30

# LOF
select lof(s1,s2) from root.test.d1 where time<1000
select lof(s1, "method"="series") from root.test.d1 where time<1000

# MissDetect
select missdetect(s2,'minlen'='10') from root.test.d2

# Range
select range(s1,"lower_bound"="101.0","upper_bound"="125.0") from root.test.d1 where time <= 2020-01-01 00:00:30

# TwoSidedFilter
select TwoSidedFilter(s0, 'len'='5', 'threshold'='0.3') from root.test

# Outlier
select outlier(s1,"r"="5.0","k"="4","w"="10","s"="5") from root.test

# MasterTrain
select MasterTrain(lo,la,m_lo,m_la,'p'='3','eta'='1.0') from root.test

# MasterDetect
select MasterDetect(lo,la,m_lo,m_la,model,'output_type'='repair','p'='3','k'='3','eta'='1.0') from root.test
select MasterDetect(lo,la,m_lo,m_la,model,'output_type'='anomaly','p'='3','k'='3','eta'='1.0') from root.test
```

### 频域分析

更多见文档[Frequency-Domain](../Reference/UDF-Libraries.md#频域分析)

```sql
# Conv
select conv(s1,s2) from root.test.d2

# Deconv
select deconv(s3,s2) from root.test.d2
select deconv(s3,s2,'result'='remainder') from root.test.d2

# DWT
select dwt(s1,"method"="haar") from root.test.d1

# FFT
select fft(s1) from root.test.d1
select fft(s1, 'result'='real', 'compress'='0.99'), fft(s1, 'result'='imag','compress'='0.99') from root.test.d1

# HighPass
select highpass(s1,'wpass'='0.45') from root.test.d1

# IFFT
select ifft(re, im, 'interval'='1m', 'start'='2021-01-01 00:00:00') from root.test.d1

# LowPass
select lowpass(s1,'wpass'='0.45') from root.test.d1
```

### 数据匹配

更多见文档[Data-Matching](../Reference/UDF-Libraries.md#数据匹配)

```sql
# Cov
select cov(s1,s2) from root.test.d2

# DTW
select dtw(s1,s2) from root.test.d2

# Pearson
select pearson(s1,s2) from root.test.d2

# PtnSym
select ptnsym(s4, 'window'='5', 'threshold'='0') from root.test.d1

# XCorr
select xcorr(s1, s2) from root.test.d1 where time <= 2020-01-01 00:00:05
```

### 数据修复

更多见文档[Data-Repairing](../Reference/UDF-Libraries.md#数据修复)

```sql
# TimestampRepair
select timestamprepair(s1,'interval'='10000') from root.test.d2
select timestamprepair(s1) from root.test.d2

# ValueFill
select valuefill(s1) from root.test.d2
select valuefill(s1,"method"="previous") from root.test.d2

# ValueRepair
select valuerepair(s1) from root.test.d2
select valuerepair(s1,'method'='LsGreedy') from root.test.d2

# MasterRepair
select MasterRepair(t1,t2,t3,m1,m2,m3) from root.test

# SeasonalRepair
select seasonalrepair(s1,'period'=3,'k'=2) from root.test.d2
select seasonalrepair(s1,'method'='improved','period'=3) from root.test.d2
```

### 序列发现

更多见文档[Series-Discovery](../Reference/UDF-Libraries.md#序列发现)

```sql
# ConsecutiveSequences
select consecutivesequences(s1,s2,'gap'='5m') from root.test.d1
select consecutivesequences(s1,s2) from root.test.d1

# ConsecutiveWindows
select consecutivewindows(s1,s2,'length'='10m') from root.test.d1
```

### 机器学习

更多见文档[Machine-Learning](../Reference/UDF-Libraries.md#机器学习)

```sql
# AR
select ar(s0,"p"="2") from root.test.d0

# Representation
select representation(s0,"tb"="3","vb"="2") from root.test.d0

# RM
select rm(s0, s1,"tb"="3","vb"="2") from root.test.d0
```

## Lambda 表达式

更多见文档[Lambda](../Reference/Function-and-Expression.md#Lambda表达式)

```sql
select jexl(temperature, 'expr'='x -> {x + x}') as jexl1, jexl(temperature, 'expr'='x -> {x * 3}') as jexl2, jexl(temperature, 'expr'='x -> {x * x}') as jexl3, jexl(temperature, 'expr'='x -> {multiply(x, 100)}') as jexl4, jexl(temperature, st, 'expr'='(x, y) -> {x + y}') as jexl5, jexl(temperature, st, str, 'expr'='(x, y, z) -> {x + y + z}') as jexl6 from root.ln.wf01.wt01;```
```

## 条件表达式

更多见文档[Conditional Expressions](../Reference/Function-and-Expression.md#条件表达式)

```sql
select T, P, case
when 1000<T and T<1050 and 1000000<P and P<1100000 then "good!"
when T<=1000 or T>=1050 then "bad temperature"
when P<=1000000 or P>=1100000 then "bad pressure"
end as `result`
from root.test1

select str, case
when str like "%cc%" then "has cc"
when str like "%dd%" then "has dd"
else "no cc and dd" end as `result`
from root.test2

select
count(case when x<=1 then 1 end) as `(-∞,1]`,
count(case when 1<x and x<=3 then 1 end) as `(1,3]`,
count(case when 3<x and x<=7 then 1 end) as `(3,7]`,
count(case when 7<x then 1 end) as `(7,+∞)`
from root.test3

select x, case x when 1 then "one" when 2 then "two" else "other" end from root.test4

select x, case x when 1 then true when 2 then false end as `result` from root.test4

select x, case x
when 1 then 1
when 2 then 222222222222222
when 3 then 3.3
when 4 then 4.4444444444444
end as `result`
from root.test4
```

## 触发器

### 使用 SQL 语句注册该触发器
```sql
// Create Trigger

createTrigger

​    : CREATE triggerType TRIGGER triggerName=identifier triggerEventClause ON pathPattern AS className=STRING_LITERAL uriClause? triggerAttributeClause?

​    ;


triggerType

​    : STATELESS | STATEFUL

​    ;


triggerEventClause

​    : (BEFORE | AFTER) INSERT

​    ;


uriClause

​    : USING URI uri

​    ;


uri

​    : STRING_LITERAL

​    ;


triggerAttributeClause

​    : WITH LR_BRACKET triggerAttribute (COMMA triggerAttribute)* RR_BRACKET

​    ;


triggerAttribute

​    : key=attributeKey operator_eq value=attributeValue

​    ;
```
#### SQL 语句示例
```sql
CREATE STATELESS TRIGGER triggerTest

BEFORE INSERT

ON root.sg.**

AS 'org.apache.iotdb.trigger.ClusterAlertingExample'

USING URI 'http://jar/ClusterAlertingExample.jar'

WITH (

​    "name" = "trigger",

​    "limit" = "100"

)
```
### 卸载触发器

#### 卸载触发器的 SQL 语法如下：
```sql
// Drop Trigger

dropTrigger

  : DROP TRIGGER triggerName=identifier

;
```
#### 示例语句
```sql
DROP TRIGGER triggerTest1
```
### 查询触发器
```sql
SHOW TRIGGERS
```
## 连续查询（Continuous Query, CQ）

### 语法

```Go
CREATE (CONTINUOUS QUERY | CQ) <cq_id> 
[RESAMPLE 
  [EVERY <every_interval>] 
  [BOUNDARY <execution_boundary_time>]
  [RANGE <start_time_offset>[, end_time_offset]] 
]
[TIMEOUT POLICY BLOCKED|DISCARD]
BEGIN 
    SELECT CLAUSE
        INTO CLAUSE
        FROM CLAUSE
        [WHERE CLAUSE]
        [GROUP BY(<group_by_interval>[, <sliding_step>]) [, level = <level>]]
        [HAVING CLAUSE]
        [FILL ({PREVIOUS | LINEAR | constant} (, interval=DURATION_LITERAL)?)]
        [LIMIT rowLimit OFFSET rowOffset]
        [ALIGN BY DEVICE]
END
```

#### 配置连续查询执行的周期性间隔
```sql
CREATE CONTINUOUS QUERY cq1

RESAMPLE EVERY 20s

BEGIN

  SELECT max_value(temperature)

  INTO root.ln.wf02.wt02(temperature_max), root.ln.wf02.wt01(temperature_max), root.ln.wf01.wt02(temperature_max), root.ln.wf01.wt01(temperature_max)

  FROM root.ln.*.*

  GROUP BY(10s)

END


\> SELECT temperature_max from root.ln.*.*;
```
#### 配置连续查询的时间窗口大小
```
CREATE CONTINUOUS QUERY cq2

RESAMPLE RANGE 40s

BEGIN

  SELECT max_value(temperature)

  INTO root.ln.wf02.wt02(temperature_max), root.ln.wf02.wt01(temperature_max), root.ln.wf01.wt02(temperature_max), root.ln.wf01.wt01(temperature_max)

  FROM root.ln.*.*

  GROUP BY(10s)

END


\> SELECT temperature_max from root.ln.*.*;
```
#### 同时配置连续查询执行的周期性间隔和时间窗口大小
```sql
CREATE CONTINUOUS QUERY cq3

RESAMPLE EVERY 20s RANGE 40s

BEGIN

  SELECT max_value(temperature)

  INTO root.ln.wf02.wt02(temperature_max), root.ln.wf02.wt01(temperature_max), root.ln.wf01.wt02(temperature_max), root.ln.wf01.wt01(temperature_max)

  FROM root.ln.*.*

  GROUP BY(10s)

  FILL(100.0)

END


\> SELECT temperature_max from root.ln.*.*;
```
#### 配置连续查询每次查询执行时间窗口的结束时间
```sql
CREATE CONTINUOUS QUERY cq4

RESAMPLE EVERY 20s RANGE 40s, 20s

BEGIN

  SELECT max_value(temperature)

  INTO root.ln.wf02.wt02(temperature_max), root.ln.wf02.wt01(temperature_max), root.ln.wf01.wt02(temperature_max), root.ln.wf01.wt01(temperature_max)

  FROM root.ln.*.*

  GROUP BY(10s)

  FILL(100.0)

END


\> SELECT temperature_max from root.ln.*.*;
```
#### 没有GROUP BY TIME子句的连续查询
```sql
CREATE CONTINUOUS QUERY cq5

RESAMPLE EVERY 20s

BEGIN

  SELECT temperature + 1

  INTO root.precalculated_sg.::(temperature)

  FROM root.ln.*.*

  align by device

END


\> SELECT temperature from root.precalculated_sg.*.* align by device;
```
### 连续查询的管理

#### 查询系统已有的连续查询

展示集群中所有的已注册的连续查询
```sql
SHOW (CONTINUOUS QUERIES | CQS) 
```
```sql
SHOW CONTINUOUS QUERIES;
```
#### 删除已有的连续查询

删除指定的名为cq_id的连续查询：

```sql
DROP (CONTINUOUS QUERY | CQ) <cq_id>
```
```sql
DROP CONTINUOUS QUERY s1_count_cq;
```
#### 作为子查询的替代品

1. 创建一个连续查询
```sql
CREATE CQ s1_count_cq 

BEGIN 

​    SELECT count(s1)  

​        INTO root.sg_count.d.count_s1

​        FROM root.sg.d

​        GROUP BY(30m)

END
```
1. 查询连续查询的结果
```sql
SELECT avg(count_s1) from root.sg_count.d;
```
## 用户自定义函数

### UDFParameters
```sql
SELECT UDF(s1, s2, 'key1'='iotdb', 'key2'='123.45') FROM root.sg.d;
```
### UDF 注册

```sql
CREATE FUNCTION <UDF-NAME> AS <UDF-CLASS-FULL-PATHNAME> (USING URI URI-STRING)?
```

#### 不指定URI
```sql
CREATE FUNCTION example AS 'org.apache.iotdb.udf.UDTFExample'
```
#### 指定URI
```sql
CREATE FUNCTION example AS 'org.apache.iotdb.udf.UDTFExample' USING URI 'http://jar/example.jar'
```
### UDF 卸载

```sql
DROP FUNCTION <UDF-NAME>
```
```sql
DROP FUNCTION example
```
### UDF 查询

#### 带自定义输入参数的查询
```sql
SELECT example(s1, 'key1'='value1', 'key2'='value2'), example(*, 'key3'='value3') FROM root.sg.d1;
```
```sql
SELECT example(s1, s2, 'key1'='value1', 'key2'='value2') FROM root.sg.d1;
```
#### 与其他查询的嵌套查询
```sql
SELECT s1, s2, example(s1, s2) FROM root.sg.d1;

SELECT *, example(*) FROM root.sg.d1 DISABLE ALIGN;

SELECT s1 * example(* / s1 + s2) FROM root.sg.d1;

SELECT s1, s2, s1 + example(s1, s2), s1 - example(s1 + example(s1, s2) / s2) FROM root.sg.d1;
```
### 查看所有注册的 UDF
```sql
SHOW FUNCTIONS
```
## 权限管理

### 用户与角色相关

- 创建用户（需 MANAGE_USER 权限)


```SQL
CREATE USER <userName> <password>
eg: CREATE USER user1 'passwd'
```

- 删除用户 (需 MANEGE_USER 权限)


```SQL
DROP USER <userName>
eg: DROP USER user1
```

- 创建角色 (需 MANAGE_ROLE 权限)

```SQL
CREATE ROLE <roleName>
eg: CREATE ROLE role1
```

- 删除角色 (需 MANAGE_ROLE 权限)


```SQL
DROP ROLE <roleName>
eg: DROP ROLE role1   
```

- 赋予用户角色 (需 MANAGE_ROLE 权限)


```SQL
GRANT ROLE <ROLENAME> TO <USERNAME>
eg: GRANT ROLE admin TO user1
```

- 移除用户角色 (需 MANAGE_ROLE 权限)


```SQL
REVOKE ROLE <ROLENAME> FROM <USER>
eg: REVOKE ROLE admin FROM user1
```

- 列出所有用户  (需 MANEGE_USER 权限)

```SQL
LIST USER
```

- 列出所有角色 (需 MANAGE_ROLE 权限)

```SQL
LIST ROLE
```

- 列出指定角色下所有用户 (需 MANEGE_USER 权限)

```SQL
LIST USER OF ROLE <roleName>
eg: LIST USER OF ROLE roleuser
```

- 列出指定用户下所有角色

用户可以列出自己的角色，但列出其他用户的角色需要拥有 MANAGE_ROLE 权限。

```SQL
LIST ROLE OF USER <username> 
eg: LIST ROLE OF USER tempuser
```

- 列出用户所有权限

用户可以列出自己的权限信息，但列出其他用户的权限需要拥有 MANAGE_USER 权限。

```SQL
LIST PRIVILEGES OF USER <username>;
eg: LIST PRIVILEGES OF USER tempuser;
    
```

- 列出角色所有权限

用户可以列出自己具有的角色的权限信息，列出其他角色的权限需要有 MANAGE_ROLE 权限。

```SQL
LIST PRIVILEGES OF ROLE <roleName>;
eg: LIST PRIVILEGES OF ROLE actor;
```

- 更新密码

用户可以更新自己的密码，但更新其他用户密码需要具备MANAGE_USER  权限。

```SQL
ALTER USER <username> SET PASSWORD <password>;
eg: ALTER USER tempuser SET PASSWORD 'newpwd';
```

### 授权与取消授权

用户使用授权语句对赋予其他用户权限，语法如下：

```SQL
GRANT <PRIVILEGES> ON <PATHS> TO ROLE/USER <NAME> [WITH GRANT OPTION]；
eg: GRANT READ ON root.** TO ROLE role1;
eg: GRANT READ_DATA, WRITE_DATA ON root.t1.** TO USER user1;
eg: GRANT READ_DATA, WRITE_DATA ON root.t1.**,root.t2.** TO USER user1;
eg: GRANT MANAGE_ROLE ON root.** TO USER user1 WITH GRANT OPTION;
eg: GRANT ALL ON root.** TO USER user1 WITH GRANT OPTION;
```

用户使用取消授权语句可以将其他的权限取消，语法如下：

```SQL
REVOKE <PRIVILEGES> ON <PATHS> FROM ROLE/USER <NAME>;
eg: REVOKE READ ON root.** FROM ROLE role1;
eg: REVOKE READ_DATA, WRITE_DATA ON root.t1.** FROM USER user1;
eg: REVOKE READ_DATA, WRITE_DATA ON root.t1.**, root.t2.** FROM USER user1;
eg: REVOKE MANAGE_ROLE ON root.** FROM USER user1;
eg: REVOKE ALL ON ROOT.** FROM USER user1;
```